There are a wide variety of known cooking techniques and there has been, within each, a great deal of experimentation with the several variables associates with such cooking techniques. For example, the use of steam as a heat transfer medium is well-known. Such steam cooking devices may employ the steam at atmospheric pressure utilizing convection heat transfer. In this regard, most commercial cooking equipment is highly specialized and include integrally designed burners specifically adapted for the particular unit. Because of the variety of such specialized forms of cooking equipment, it has not been possible to effectively optimize the manufacturer of such equipment. Moreover, the design of present commercial cooking equipment has focused primarily on speed and capacity of cooking with little regard to energy utilization efficiencies. Additionally, little significance has been placed on the production of the food product itself. That is, whether the food product is substantially cooked in order to avoid harmful bacteria or overcooked generating mutagens or carcinogens which are likewise undesirable for human consumption.
There has been a significant amount of research into eating habits as they relate to health. For example, in the article Prevention of Formation of Important Mutagens/Carcinogens in the Human Food Chain by Weisburger and Jones, it is pointed out that during cooking (typically frying or boiling) leading to the browning of meat or fish, mutagens or carcinogens are frequently generated. The article suggests the desirability of finding ways to lower or prevent the formation of these undesirable products during cooking. One scheme for lowering these undesirable products is to reduce the surface temperature during cooking. Another is to add additives to the meat or fish prior to the cooking process.
From the above article, it appears that the undesirable mutagens or carcinogens will be generated on the food surface during cooking, for example, of hamburger on a conventional hot grill and that these undesirable products will be scraped off the grill with the meat and placed in the consumer's sandwich.
The current method for cooking hamburger, for example, requires a lot of fat for three reasons. The fat acts as a release agent preventing the meat from sticking to the griddle and acts as a heat transfer medium itself. Finally, the fact provides the juiciness in the finished sandwich. The undesirability of the conventional "fast food" approach to cooking beef for sandwiches on a hot grill is now apparent.
In order to avoid the creation of such mutagens and carcinogens is to lower the cooking temperatures which not only reduces or eliminates the formation of such mutagens and carcinogens, but also provides a more palatable product. Exposing the meat to high temperatures causes the fibers in the meat to shrink, purging the meat of its natural juices. Such high temperature cooking also cooks the outer surface to its "done" state prior to the interior reaching that "done" condition. Thus, the outer portions are frequently comparatively overcooked, dry and tough while the interior is left virtually uncooked. Reducing cooking temperatures ensures that the food product will not only not be overcooked on the outside, but will be substantially cooked on the inside regardless of the time the food product is subjected to that reduced temperature.
As noted hereinabove, while overcooking of an outer surface of the food product is of concern, under cooking of the interior of the food product is likewise is of a significant health concern. It is a common occurrence that the interior portion of a hamburger is often left under cooked with this under cooking of the hamburger being a main cause of poisoning from E. coli. Often times, restaurant owners are fearful of under cooking the food product to the extent that the outer portion of the food product becomes significantly over cooked resulting in the above-noted problems as well as dryness of the product. Accordingly, in order to provide the consumer with a palatable product, the meat product is often times left under cooked in the interior and consequently can result in significant consumer health problems.
In addition to the foregoing issues relating to consumer health, direct energy consumption, which can be significant in commercial cooking, as well as other indirect energy consumptions, also can have an important economic impact. For example, in restaurants, fast food eating establishments, institutions and the like, griddles generate significant heating effects in the kitchen, create cooking odors and if gas fired, draw combustion air from the kitchen to generate combustion gases. In such establishments, it is common practice to employ large exhaust hoods above the cooking device for maintaining the kitchen in a properly vented condition, with the kitchen area likewise being air-conditioned on a continuous basis. Accordingly, due to the high cost of energy, improvements in either direct or indirect energy utilization, is also of a concern.
One effort to overcome the aforementioned shortcomings set forth in U.S. Pat. No. 4,660,542 issued to Scherer which discloses a cooking system particularly adaptable for commercial or institutional usage which includes a closed loop heat transfer circuit having a heating and vaporization zone which is adaptable to a griddle type cooking arrangement. However, the arrangement set forth therein merely passes a heating medium in the form of water vapor through a conduit system underlying a surface of the griddle in order to heat such griddle. This conduit system is similar to a radiator wherein the conduits are heated by the heating medium which subsequently heats the air below an underside of the griddle cooking surface a consequently the cooking surface itself. In this regard, the areas of the cooking surface directly adjacent the conduits are consequently heated to a greater degree than those portions of the heating surface which are not directly adjacent to a conduit. Moreover, should one or more of the conduits become slogged due to deposits in the heating medium, this non-uniform heating of the cooking surface would be exaggerated. Accordingly, the effect of such a system is not that different than an electrical or gas heated griddle.
Clearly, there is a need for a griddle type heating surface wherein a temperature of the griddle heating surface is substantially uniform across the entire surface. Moreover, there is a need for a griddle type cooking device wherein portions of the griddle heating surface are not permitted to increase to an excessive temperature. Additionally, there is a need for a griddle type cooking surface wherein under cooking of the food product is minimized thereby providing for a more healthy food product.